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The Rainbow hydrothermal field (36° N Mid-Atlantic Ridge) is one of the three presently known fields related to serpentinization of ultramafic rocks accompanied by the formation of hydrogen- and methane-rich solutions. Gas chromatographic (GC) and molecular gas chromatographic–mass spectrometric (GC-MS) investigations of sulfide ores and sediments from this field confirmed a predominantly biological nature of bitumoids related to the high-temperature transformation of biomass of the hydrothermal biological community. At the same time, ores of the Rainbow field contain significant amounts of compounds that are not directly related to biogenic synthesis. This fact suggests the possibility of an abiogenic synthesis of methane and even complex hydrocarbons during the serpentinization of ultramafic rocks. 相似文献
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This study presents data on Fe–Mn nodules first recovered from the northeastern part of the Kara Sea. Analysis of the geochemical indicators of organic matter and major and trace element compositions of nodules showed that samples with strong Mn enrichment (Mn/Fe = 2.38, on average) are dominated by terrestrial organic matter (OM), whereas Fe-rich samples (Mn/Fe = 0.20, on average) are dominated by marine biogenic OM. The variation in the n-alkane abundances in the studied nodules is independent of the sampling sites and nodule morphology. This study was conducted for the first time in the Artic region.
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The investigation of the bottom of Lake Baikal carried out during the 2008 summer season by means of Mir manned deep-submergence
vehicles resulted in the recovery of a series of sediments, ferruginous crusts, and peculiar mineralized tubes several centimeters
high and up to 2–6 cm in diameter. According to the scanning electron investigation, these formations consist mainly of the
enclosing sediment particles and biogcnie silica cemented by iron and minor manganese hydroxides. The chemical composition
of the tubes is similar to both that of the enclosing sediments and slightly ferruginous crusts and nodules, but the tubes
and crusts are somewhat richer relative to the sediments in some microelements, namely, arsenic, cadmium, and uranium. In
general, the structure and composition of these tubes reminds one of the worm tubes common in the sediments of a number of
seas. The investigation of the rare earth elements in some samples or ferruginous formations and sediments revealed a positive
europium anomaly, which might be related to either the composition of the surrounding continental magmatic rocks or to the
influence of hypothetical hydrothermal solutions. 相似文献
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M. A. Levitan O. V. Levchenko I. O. Murdmaa V. I. Peresypkin I. A. Roshchina A. V. Tolmacheva 《Lithology and Mineral Resources》2008,43(6):520-541
Lithology, heavy mineral associations, and chemical composition of sediments studied in two gravity cores from Isfjord, Western Spitsbergen, accompanied by high-frequency seismic records, provide a new insight on the provenance and glaciomarine sedimentation in the fjord from the last deglaciation through the Holocene. 相似文献
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The optimum conditions were selected for the chromatographic separation of model mixtures of C12–C40
n-alkanes. For one of the samples of hydrothermal deposits, the extraction conditions of the hydrocarbons were studied and
a sample preparation procedure was selected. A procedure is proposed to determine the n-alkanes in samples of hydrothermal deposits by means of gas chromatography-mass spectrometry (GC-MS). The detection limit
for the n-alkanes amounted to 3 × 10−9 to 10−8% depending on the components. On the basis of the procedure proposed, the composition of the n-alkanes was studied in the samples of hydrothermal deposits collected at the Mid-Atlantic Ridge (the Broken Spur, Lost City,
and Rainbow fields). The analysis performed showed that the samples treated contained C14-C35
n-alkanes. The concentrations of the n-alkanes considered were rather low and varied from 0.002 to 0.038 μg/g. Hypotheses concerning the genesis of the n-alkanes identified were formed. 相似文献
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O. M. Khlystov T. I. Zemskaya T. Ya. Sitnikova I. V. Mekhanikova I. A. Kaigorodova A. G. Gorshkov O. A. Timoshkin O. V. Shubenkova S. M. Chernitsyna A. V. Lomakina A. V. Likhoshvai A. M. Sagalevich V. I. Moskvin V. I. Peresypkin N. A. Belyaev M. V. Slipenchuk A. K. Tulokhonov M. A. Grachev 《Doklady Earth Sciences》2009,429(1):1333-1336